#!/bin/sh

# Parses DHCP options from openvpn to update resolv.conf
# To use set as 'up' and 'down' script in your openvpn *.conf:
# up /etc/openvpn/update-resolv-conf
# down /etc/openvpn/update-resolv-conf
#
# Used snippets of resolvconf script by Thomas Hood <jdthood@yahoo.co.uk>
# and Chris Hanson
# Licensed under the GNU GPL.  See /usr/share/common-licenses/GPL.
# 07/2013 colin@daedrum.net Fixed intet name
# 05/2006 chlauber@bnc.ch
#
# Example envs set from openvpn:
# foreign_option_1='dhcp-option DNS 193.43.27.132'
# foreign_option_2='dhcp-option DNS 193.43.27.133'
# foreign_option_3='dhcp-option DOMAIN be.bnc.ch'
# foreign_option_4='dhcp-option DOMAIN-SEARCH bnc.local'

RESOLVCONF=/usr/bin/resolvconf

case $script_type in

up)
    IFS='
'
    for option in $(env | grep "foreign_option_" | sed "s/\w\+=//"); do
        echo "$option"
        part1=$(echo "$option" | cut -d " " -f 1)
        if [ "$part1" = "dhcp-option" ]; then
            part2=$(echo "$option" | cut -d " " -f 2)
            part3=$(echo "$option" | cut -d " " -f 3)
            if [ "$part2" = "DNS" ]; then
                IF_DNS_NAMESERVERS="$IF_DNS_NAMESERVERS $part3"
            fi
            if [ "$part2" = "DOMAIN" ] || [ "$part2" = "DOMAIN-SEARCH" ]; then
                IF_DNS_SEARCH="$IF_DNS_SEARCH $part3"
            fi
        fi
    done
    R=""
    if [ "$IF_DNS_SEARCH" ]; then
        R="search "
        for DS in $IF_DNS_SEARCH; do
            R="${R} $DS"
        done
        R="${R}
"
    fi

    for NS in $IF_DNS_NAMESERVERS; do
        R="${R}nameserver $NS
"
    done
    printf "%s" "$R" | $RESOLVCONF -x -a "${dev}.inet"
    ;;
down)
    $RESOLVCONF -d "${dev}.inet"
    ;;
esac

# Workaround / jm@epiclabs.io
# force exit with no errors. Due to an apparent conflict with the Network Manager
# $RESOLVCONF sometimes exits with error code 6 even though it has performed the
# action correctly and OpenVPN shuts down.
exit 0
